Packed cork — Virgin cork, raw reproduction cork, burnt cork, boiled reproduction cork and raw cork waste — Determination of moisture content
1Key Takeaways
This document specifies a method for determination of the moisture content of packed cork, either virgin cork, raw reproduction cork, burnt cork, boiled reproduction cork and raw cork waste.
2Expert Interpretation
Professional interpretation of the ISO 2386:2019 standard on the moisture content determination method of five types of cork materials, including virgin cork, recycled cork, and charred cork, including the test principle, equipment requirements, operating procedures and result calculation specifications, which is suitable for quality control of cork packaging materials.
Analysis of the core content of the standard
This standard specifies the determination method of moisture content of five types of cork materials for packaging, including virgin cork, recycled raw cork, and burnt cork. The test principle is based on the mass loss method, and moisture separation is achieved through (103±2)℃ drying treatment.
Key test equipment requirements
| Equipment type | Technical parameters | Standard terms |
|---|---|---|
| Analytical balance | Resolution ≥ 0.5g | 5.1 |
| Drying oven | Forced ventilation type, 103±2℃ | 5.2 |
| Dryer | Equipped with effective desiccant (silica gel/calcium chloride) | 5.4 |
Test process essentials
- Randomly select 3 400g samples (6.1)
- Container pretreatment: drying at 103℃ for 30min → cooling in dryer for 30min (6.2)
- Weigh and record the container mass m1 and the initial mass of the sample m2
- Dry in a cycle until constant weight (difference between two consecutive weighings ≤0.5g), record m3
Actual application case
A cork stopper manufacturer used this standard to test and found that the average moisture content of boiled regenerated cork reached 8%, exceeding the upper limit of 5% required by the process. By adjusting the drying time from 1h to 2.5h, the dimensional stability of the product was significantly improved.
Technical Evolution of Standards
Main changes compared to the 2015 version: ①The title is modified to include five types of cork; ②The second paragraph of 5.3 is deleted and moved to the first paragraph of 6.2; ③The description of the weighing frequency at the end of 6.2 is deleted. This reflects the optimization of the test process description in the standard.
Implementation Suggestions
- It is recommended to increase the number of samples to 5 to improve representativeness
- Desiccant should be replaced monthly to ensure moisture absorption efficiency
- For high-density virgin cork, it is recommended to extend the first drying time to 2h